Saw teeth for circular saws of the type mounted on a feller head for a tree felling apparatus are known. U.S. Pat. No. 4,932,447, Morin, 1990, and U.S. Pat. No. 5,205,199, MacLennan, 1993, represent saw teeth that have become well known in the industry. Morin '447 and MacLennan '199 both teach a replaceable saw tooth with four sides. The teeth can be rotated when the active cutting tips and edges become dull or worn.
Saw teeth wear relatively quickly and may become rounded or dull. This may cause increased fuel consumption, decreased productivity, or poor cut quality, or all of them, and may tend to result in a need for maintenance. The cutting tips do the majority of the cutting of the tree fibers and even though the teeth may have large cutting tips, only a small area at the end of the tip is used. As the tip wears it may tend to become rounded and the tooth body immediately behind the end of the tip may then present the outermost part of the tooth. This portion of the tooth body may then contact the tree before, or rather than, the point of the rounded cutting tip. This may tend to result in increased friction and the tearing of tree fibers, instead of cutting the tree fibers with a shearing action. This may tend to consume more energy, decrease machine productivity and produce a rougher cut on the tree butt. A dull tooth may impose higher forces and stresses on the saw blade than a sharp tooth.
The outermost cutting tips of the teeth are also susceptible to damage from impact, such as when the teeth strike objects such as rocks and other debris during the felling of trees. This may also lead to a need for maintenance.
Some teeth have carbide wear plates with sharp corners at the cutting tips. These corners may tend to chip or break off easily when striking objects or debris. This may result in a loss of the cutting edge and in a loss of cutting efficiency. Other teeth may have flat plateaus at the cutting tips. These may be more durable but may become rounded or dull faster and may be less efficient at cutting tree fibers.
The use of a small radius as described herein by the present inventor may prevent this and may result in a more durable carbide tip while still retaining a relatively sharp point to have efficient cutting.